Sudden bilateral deafness in a patient with vertebrobasilar artery occlusion: A case report

Rationale: Sudden bilateral deafness is often associated with serious systematic conditions such as neoplasms, vascular events, autoimmune diseases, infections, and iatrogenic injury, but very rarely to cerebrovascular disease. This is a rare case of sudden bilateral deafness in a patient with the vertebrobasilar artery occlusion. Patient concerns: A 46-year-old man was admitted to a local hospital for sudden bilateral deafness, the patient suffered inarticulate speech and walking unsteadily 6 days later. Diagnoses: Difusion-weighted magnetic resonance imagin demonstrated acute cerebral infarction in the pons and bilateral cerebellum; Magnetic resonance angiography showed vertebrobasilar artery occlusion. Interventions: Aspirin and clopidogrel were given for antiplatelet therapy, revascularization was obtained by endovascular treatment. Outcomes: The symptoms of dysarthria, ataxia and weakness gradually improved and were discharged 14 days after admission revascularization. After 3 months telephone followed-up the patient was self-cared. Lessons: Deafness sometimes can be an early warning sign of impending vertebrobasilar ischemic stroke. Early recognition of deafness with acute ischemic stroke should allow special management, and misdiagnosis may result in significant morbidity, or even mortality.


Introduction
Sudden bilateral deafness is often associated with serious systematic conditions such as neoplasms, vascular events, autoimmune diseases, infections, and iatrogenic injury, but very rarely to cerebrovascular disease.However, deafness sometimes can be an early warning sign of impending vertebrobasilar ischemic stroke because the blood supply to the auditory originates from vertebrobasilar system.Early recognition of deafness with acute ischemic stroke should allow special management, and misdiagnosis may result in significant morbidity, or even mortality.
Sudden deafness has been considered traditionally to be a neglected and underestimated symptom of stroke.Because the anterior-inferior cerebellar artery (AICA) which supply the blood to the auditory system originates from the posterior circulation, sometimes patients with cerebral infarction in the posterior circulation can present with sudden deafness. [1][4] Because the early diagnosis and proper management may provide a window to prevent the progression of infarction to larger areas, misdiagnosis may result in significant morbidity and mortality.We report a patient suffered bilateral deafness as initial symptoms 6 days prior to permanent infarction.

Case presentation
A 46-year-old man with a history of hypertension, smoking and alcohol was admitted to local hospital for sudden bilateral deafness, he was diagnosed as sudden deafness and given alprostadil for intravenous injection.His home medications included 20 mg twice daily of nifedipine.His deafness was completely improved.But the patient suffered inarticulate speech and walking unsteadily 6 days later, he was transferred to our department with head computed tomography returned no signifcant fndings (Fig. 1).On admission his neurological examination revealed dysarthria, nystagmus and ataxia, the National Institute of Health Stroke Scale score was 3. His blood pressure was 160/80 mm Hg, his pulse rate was 70 beats/minute, and his temperature was 36.8°C.His general physical examination was unremarkable.Her laboratory test results showed no obvious abnormalities.Difusion-weighted magnetic resonance imagin demonstrated acute cerebral infarction in the pons and bilateral cerebellum; Magnetic resonance angiography showed vertebrobasilar artery occlusion (Fig. 2).
The delivery of recombinant tissue plasminogen activator (rtPA) has been the standard of care in patients with acute ischemic stroke.However, rtPA must be administered within 4.5h of stroke onset, and it has been 10 hours after the neurologic symptom appeared when he arrived in my hospital.Aspirin and clopidogrel and tirofiban were given for antiplatelet therapy, but his condition was gradually dropped and the strength in his right limb dropped to III level 3 days after his admission.Digital subtraction cerebral angiography showed the right vertebral artery was nondominant artery and subtotal occluded in the V4 segment; the left vertebral artery was total occluded in the V2 segment (Fig. 3).Fortunately, revascularization was obtained by endovascular treatment (Fig. 4), though dysarthria, ataxia and weakness were still remained, he was discharged 14 days after his admission with the the National Institute of Health Stroke Scale scored 7.After 3 months telephone followed-up the patient was self-cared, and the modified rankin scale score was 0.

Discussion
We report a patient suffered bilateral deafness as initial symptoms 6 days prior to vertebrobasilar system infarction.Fortunately, revascularization was obtained by endovascular treatment and his physical condition was gradually improved.It suggested that deafness sometimes can be an early warning sign of impending vertebrobasilar ischemic stroke.Early recognition of deafness with acute ischemic stroke is very important, because vertebrobasilar ischemia is life threatening and proper  Sudden-onset deafness is often due to otolaryngologic and very rarely to cerebrovascular disease.However, because AICA which supply the blood to the auditory system originates from the posterior circulation, sometimes patients with cerebral infarction in the posterior circulation can present with sudden deafness. [5][8] Because the labyrinth requires high-energy metabolism and receives its sole supply from the IAA, the labyrinth is especially vulnerable to ischemia.11] At the same time, AICA constantly supplies the peripheral vestibular structures such as the inner ear and vestibulocochlear nerve, in addition to the central vestibular structures. [12]As a result, in contrast to other cerebellar artery territory infarction, complete AICA infarction usually results in combined peripheral and central vestibular damages. [13,14]Identifying stroke among patients presenting with deafness is one of the most challenging issues in neurology and emergency medicine.Sudden deafness in patients with risk factors of cerebrovascular disease should be prioritized for stroke workup. [15,16]t the time of admission to his local hospital, the patient in our case presented with only bilateral hearing loss without any other neurological deficits, consequently, initially he was not suspected specifc anomalies including vertebrobasilar impairment.[12][13][14] Deafness sometimes is an early warning sign of impending vertebrobasilar ischemic stroke.The rtPA has been the standard of care in patients with acute ischemic stroke.However, it has been 10 hours after the neurologic symptom appeared.Though antiplatelet therapy was given, his condition was gradually dropped.[19] Fortunately, though the patient had dysarthria, ataxia and weakness, the condition was gradually improved after the revascularization by endovascular treatment.
Although deafness can present as a sign of AICA infarction, the incidence differs from a low of 30 % to a high of 100 %. [20] There were 2 factors inclued: on the 1 hand neurologists have not included the audiogram as a routine diagnostic tool for the AICA infarction; on the other hand, patients might not be aware of the hearing loss during an attack of vertigo when the unilateral hearing loss is mild or the vertigo is severe. [21] recent study [22] on the long-term outcome suggest that recovery of hearing loss of a vascular cause is more common than previously thought, approximately 65 % of the patients due to posterior circulation ischemic stroke showed a partial or  complete hearing recovery followed at least 1 year after the onset. [23]

Conclusion
This is a rare case of sudden bilateral deafness in a patient with the vertebrobasilar artery occlusion.The delayed diagnosis of ischemic stroke in the posterior circulation might be poorly outcome and life threatening.Fortunately, our case had a good outcome after the revascularization by endovascular treatment.The early diagnosis and the proper management may provide a window to prevent the progression of infarction to larger areas.We emphasis that the possibility of vertebrobasilar occlusive disorder should be considered for patients with sudden deafness especially those with risk factors for stroke, even though no neurological signs were found.

Figure 1 .
Figure 1.Head computed tomography showed no new lesions in the area of the cerebellar hemispheres and brainstem.

Figure 2 .
Figure 2. Diffusion-weighted brain MRI showing acute multifocal lesions involving the bilateral cerebellar hemispheres, and the vertebrobasilar artery were occluded on MRA.MRA = magnetic resonance angiography, MRI = magnetic resonance imagin.

Figure 3 .
Figure 3. Anteroposterior right vertebral angiography revealed the right vertebral artery was nondominant artery and subtotal occluded in the V4 segment; Anteroposterior left vertebral angiography revealed the left vertebral artery was total occluded in the V2 segment.

Figure 4 .
Figure 4. Post-thrombectomy, the last lateralposition left vertebral angiogram demonstrated total recanalization of the BA trunk including the AICA and SCA.AICA = the anterior-inferior cerebellar artery, SCA = superior cerebellar artery.